||Interfacial Reaction between Zn-25Sn-xTi Pb-free Solder Alloys and Cu Substrate under Multiple Reflow
||Department of Materials Science and Engineering
High-Temperature Lead-Free Solder
界面反應微觀結構觀察結果顯示，一到五次多重迴焊之後Zn-25Sn-xTi 與銅基材間會生成Cu5Zn8 及 CuZn5 兩種不同介金屬化合物，當Zn-25Sn-xTi與銅結合之後，鈦含量為0.02wt%時，界面介金屬化合物總厚度出現極大值。 介金屬化合物在一到五次多重迴焊後在界面處形成，其厚度隨著隨著多種迴焊增加而增加。 經過10次多重迴焊後第三種介金屬化合物層出現，其鑑定為CuZn。 本多重迴焊也在較低溫度（220°C）下進行，CuZn5的厚度隨著鈦添加量的增加而減少，介金屬化合物總厚度沒有明顯變化。高溫Zn-25Sn-xTi的反應機制以及時效熱處理實驗結構顯示，隨著添加鈦元素的增加，界面反應和介金屬化合物的生長速率也增加。
The microstructure and growth behavior of intermetallic compound (IMC) formed between Zn-25Sn-xTi (x = 0,0.02,0.05,0.08) and Cu were investigated at high temperature (415°C) and low temperature (220°C) in this study. Microstructure observation of the solder alloys at high temperature shows that CuZn5, Cu5Zn8, CuZn were formed at the interface. The CuZn5 and Cu5Zn8 IMC were formed at the interface after one reflow. The thickness increased with increasing reflow number up to 10. After ten reflows, a third IMC layer appeared with the same planar shape and identified to be CuZn. The growth mechanisms were investigated and showed that Cu5Zn8 growth follows diffusion controlled reaction, while the CuZn5 follows reaction controlled mechanism. The multiple reflow experiment was also conducted in lower temperature (220°C) for the as-reflowed joint. The thickness of CuZn5 decreased with the increase of the titanium added although no apparent change of total IMC thickness. After establishing the IMC growth mechanism of the high temperature Zn-25Sn-xTi solders, the specimens aged to investigate its interfacial reaction behavior during aging. The growth rate of the IMC increased with the increase of the titanium added.
List of Tables 5
List of Figures 6
I. Introduction 11
1.1 Overview 11
1.2 Research Motivation 12
II. Literature Review 14
2.1 Electronic Packaging 14
2.1.1 Electronic Packaging Level 15
2.2 Solder Joint Technologies 17
2.2.1 Through-Hole Technology 17
2.2.2 Surface Mount Technology 20
2.3 Conventional High Temperature Sn-Pb alloy 23
2.4 High-Temperature Lead-Free solder 25
2.4.1 Bi-Ag Alloy 27
2.4.2 Au-Sn Alloy 27
2.4.3 Zn-Al Alloy 29
2.4.4 Zn-Sn Alloy 31
2.5 Reflow Profile 33
2.6 Solder Composition and Interfacial Reaction 37
2.7 Kinetics of Interfacial Reaction 38
2.7.1 Diffusion Controlled Reaction 43
2.7.2 Reaction Controlled Process 45
III. Methodology 46
3.1 Materials 46
3.2 Instruments 46
3.3 Experimental Process 47
3.3.1 Preparation of High-Temperature Lead-Free Zn-25Sn-xTi Solder Alloy 47
3.3.2 Substrate Preparation 49
3.3.3 The Microstructure Investigation of Lead-Free Zn-25Sn-xTi Solders 49
3.3.4 Interfacial Microstructure and Composition Analysis of Zn-25Sn-xTi/Cu Joint 55
3.3.5 High Temperature Ageing of Lead-Free Zn-25Sn-xTi/Cu Joint 55
3.3.6 Multiple Reflow Treatment of The Zn-25Sn-xTi/Cu Joint 55
IV. Results and Discussions 56
4.1 Interfacial Morphology Analysis of Liquid/Solid Reaction of Zn-25Sn-xTi and Copper Substrate at T = 415°C 56
4.2 Interfacial Reaction of Zn-25Sn-xTi/Copper Substrate under High Temperature Reflow at 415°C 79
4.3 Interfacial Reactions of Zn-25Sn-xTi/Copper Substrate under Low Temperature Reflow at 220°C 89
4.4 Activation Energy of IMC Growth under Liquid/Solid Reaction (T = 385°C, 415°C, 435°C) 97
V. Conclusions 106
 G. Ghosh, "Interfacial microstructure and the kinetics of interfacial reaction in diffusion couples between Sn–Pb solder and Cu/Ni/Pd metallization," Acta Materialia, vol. 48, no. 14, pp. 3719-3738, 2000.
 C.-M. Chen, K.-J. Wang, and K.-C. Chen, "Isothermal solid-state aging of Pb–5Sn solder bump on Ni/Cu/Ti under bump metallization," Journal of Alloys and Compounds, vol. 432, no. 1, pp. 122-128, 2007.
 I. T. Moura, C. L. Silva, N. Cheung, P. R. Goulart, A. Garcia, and J. E. Spinelli, "Cellular to dendritic transition during transient solidification of a eutectic Sn–0.7 wt% Cu solder alloy," Materials Chemistry and Physics, vol. 132, no. 1, pp. 203-209, 2012.
 R. Directive, "Directive 2002/95/EC of the European Parliament and of the Council of 27 January 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment," Official Journal of the European Union, vol. 13, p. L37, 2003.
 J.-M. Song, H.-Y. Chuang, and Z.-M. Wu, "Interfacial reactions between Bi-Ag high-temperature solders and metallic substrates," Journal of Electronic Materials, vol. 35, no. 5, pp. 1041-1049, 2006.
 M. Islam, Y. Chan, M. Rizvi, and W. Jillek, "Investigations of interfacial reactions of Sn–Zn based and Sn–Ag–Cu lead-free solder alloys as replacement for Sn–Pb solder," Journal of Alloys and Compounds, vol. 400, no. 1-2, pp. 136-144, 2005.
 C.-H. Wang and S.-W. Chen, "Sn–0.7 wt.% Cu/Ni interfacial reactions at 250 C," Acta Materialia, vol. 54, no. 1, pp. 247-253, 2006.
 K. Kim, S. Huh, and K. Suganuma, "Effects of intermetallic compounds on properties of Sn–Ag–Cu lead-free soldered joints," Journal of Alloys and Compounds, vol. 352, no. 1-2, pp. 226-236, 2003.
 C.-H. Wang and C.-Y. Kuo, "Growth kinetics of the solid-state interfacial reactions in the Sn–Cu/Co and Sn/Co–Cu couples," Materials Chemistry and Physics, vol. 130, no. 1-2, pp. 651-656, 2011.
 S.-W. Chen, C.-F. Yang, H.-J. Wu, R.-B. Chang, and C.-M. Hsu, "Interfacial reactions in the Sn–In–Zn/Ag and Sn–In–Zn/Ni couples," Materials Chemistry and Physics, vol. 132, no. 2-3, pp. 481-487, 2012.
 M. Rettenmayr, P. Lambracht, B. Kempf, and C. Tschudin, "Zn-Al based alloys as Pb-free solders for die attach," Journal of Electronic Materials, vol. 31, no. 4, pp. 278-285, 2002.
 T. Shimizu, H. Ishikawa, I. Ohnuma, and K. Ishida, "Zn-Al-Mg-Ga alloys as Pb-free solder for die-attaching use," Journal of Electronic Materials, vol. 28, no. 11, pp. 1172-1175, 1999.
 A. Haque, B. Lim, A. Haseeb, and H. Masjuki, "Die attach properties of Zn–Al–Mg–Ga based high-temperature lead-free solder on Cu lead-frame," Journal of Materials Science: Materials in Electronics, vol. 23, no. 1, pp. 115-123, 2012.
 K. Suganuma, "Japan patent 2004-237375 (26 August 2004)," Google Scholar.
 J.-E. Lee, K.-S. Kim, K. Suganuma, M. Inoue, and G. Izuta, "Thermal properties and phase stability of Zn-Sn and Zn-In alloys as high temperature lead-free solder," Materials Transactions, vol. 48, no. 3, pp. 584-593, 2007.
 K. Suganuma, S.-J. Kim, and K.-S. Kim, "High-temperature lead-free solders: properties and possibilities," JOM, vol. 61, no. 1, pp. 64-71, 2009.
 X. Hiao, Introduction to semiconductor manufacturing technology. Prentice Hall, pp.11-17, 2000.
 D. D. Chung, Materials for electronic packaging. Elsevier, pp.3-6, 1995.
 P. Vianco and Y. Feng, "Electronic Packaging: Solder Mounting Technologies," pp.1-11, 2014.
 N.-C. Lee, Reflow Soldering Processes. Elsevier, pp.1-18, 2002.
 F. W. Gayle, G. Becka, A. Syed, J. Badgett, G. Whitten, T.-Y. Pan, A. Grusd, B. Bauer, R. Lathrop, and J. Slattery, "High temperature lead-free solder for microelectronics," JOM, vol. 53, no. 6, pp. 17-21, 2001.
 S. Kim, K.-S. Kim, S.-S. Kim, K. Suganuma, and G. Izuta, "Improving the Reliability of Si Die Attachment with Zn-Sn-Based High-Temperature Pb-Free Solder Using a TiN Diffusion Barrier," Journal of Electronic Materials, vol. 38, no. 12, pp. 2668-2675, 2009.
 Y. Yamada, Y. Takaku, Y. Yagi, Y. Nishibe, I. Ohnuma, Y. Sutou, R. Kainuma, and K. Ishida, "Pb-free high temperature solders for power device packaging," Microelectronics Reliability, vol. 46, no. 9-11, pp. 1932-1937, 2006.
 L. Quan, D. Frear, D. Grivas, and J. Morris, "Tensile behavior of Pb-Sn solder/Cu joints," Journal of Electronic Materials, vol. 16, no. 3, pp. 203-208, 1987.
 S. Menon, E. George, M. Osterman, and M. Pecht, "High lead solder (over 85%) solder in the electronics industry: RoHS exemptions and alternatives," Journal of Materials Science: Materials in Electronics, vol. 26, no. 6, pp. 4021-4030, 2015.
 H. Wang, X. Ma, F. Gao, and Y. Qian, "Sn concentration on the reactive wetting of high-Pb solder on Cu substrate," Materials Chemistry and Physics, vol. 99, no. 2-3, pp. 202-205, 2006.
 M. Harada and R. Satoh, "Mechanical characteristics of 96.5 Sn/3.5 Ag solder in microbonding," IEEE Transactions on Components, Hybrids, and Manufacturing Technology, vol. 13, no. 4, pp. 736-742, 1990.
 M. McCormack, S. Jin, G. Kammlott, and H. Chen, "New Pb‐free solder alloy with superior mechanical properties," Applied Physics Letters, vol. 63, no. 1, pp. 15-17, 1993.
 T. B. Massalski, J. Murray, L. Bennett, and H. Baker, "Binary Alloy Phase Diagrams, vol.3," ASM International, Metals Park, OH, 1986.
 G. Zeng, S. McDonald, and K. Nogita, "Development of high-temperature solders," Microelectronics Reliability, vol. 52, no. 7, pp. 1306-1322, 2012.
 S. A. Musa, M. Salleh, M. A. Anuar, and S. Norainiza, "Zn-Sn based high temperature solder-A short review," in Advanced Materials Research, 2013, vol. 795, pp. 518-521: Trans Tech Publ.
 S.-J. Kim, K.-S. Kim, S.-S. Kim, C.-Y. Kang, and K. Suganuma, "Characteristics of Zn-Al-Cu alloys for high temperature solder application," Materials Transactions, vol. 49, no. 7, pp. 1531-1536, 2008.
 H. R. Kotadia, O. Mokhtari, M. Bottrill, M. P. Clode, M. A. Green, and S. H. Mannan, "Reactions of Sn-3.5Ag-Based Solders Containing Zn and Al Additions on Cu and Ni(P) Substrates," Journal of Electronic Materials, vol. 39, no. 12, pp. 2720-2731, 2010.
 N. Kang, H. S. Na, S. J. Kim, and C. Y. Kang, "Alloy design of Zn–Al–Cu solder for ultra high temperatures," Journal of Alloys and Compounds, vol. 467, no. 1-2, pp. 246-250, 2009.
 J. N. Lalena, N. F. Dean, and M. W. Weiser, "Experimental investigation of Ge-doped Bi-11Ag as a new Pb-free solder alloy for power die attachment," Journal of Electronic Materials, vol. 31, no. 11, pp. 1244-1249, 2002.
 Y. Shi, W. Fang, Z. Xia, Y. Lei, F. Guo, and X. Li, "Investigation of rare earth-doped BiAg high-temperature solders," Journal of Materials Science: Materials in Electronics, vol. 21, no. 9, pp. 875-881, 2010.
 X. Liu, M. H. Hu, H. K. Nguyen, C. G. Caneau, M. H. Rasmussen, R. W. Davis, and C. E. Zah, "Comparison Between Epi-Down and Epi-Up Bonded High-Power Single-Mode 980-nm Semiconductor Lasers," IEEE Transactions on Advanced Packaging, vol. 27, no. 4, pp. 640-646, 2004.
 Y. C. Liu, J. W. R. Teo, S. K. Tung, and K. H. Lam, "High-temperature creep and hardness of eutectic 80Au/20Sn solder," Journal of Alloys and Compounds, vol. 448, no. 1-2, pp. 340-343, 2008.
 J. I. Sasaki, M. Itoh, T. Tamanuki, H. Hatakeyama, S. Kitamura, T. Shimoda, and T. Kato, "Multiple-chip precise self-aligned assembly for hybrid integrated optical modules using Au-Sn solder bumps," IEEE transactions on Advanced Packaging, vol. 24, no. 4, pp. 569-575, 2001.
 H. Okamoto and T. Massalski, "The Au− Sn (Gold-tin) system," Bulletin of Alloy Phase Diagrams, vol. 5, no. 5, p. 492, 1984.
 Y. Liu, J. Teo, S. Tung, and K. Lam, "High-temperature creep and hardness of eutectic 80Au/20Sn solder," Journal of Alloys and Compounds, vol. 448, no. 1-2, pp. 340-343, 2008.
 X. Liu, M. H. Hu, H. K. Nguyen, C. G. Caneau, M. H. Rasmussen, R. W. Davis, and C.-E. Zah, "Comparison between epi-down and epi-up bonded high-power single-mode 980-nm semiconductor lasers," IEEE Transactions on Advanced Packaging, vol. 27, no. 4, pp. 640-646, 2004.
 Y. Takaku, K. Makino, K. Watanabe, I. Ohnuma, R. Kainuma, Y. Yamada, Y. Yagi, I. Nakagawa, T. Atsumi, and K. Ishida, "Interfacial Reaction between Zn-Al-Based High-Temperature Solders and Ni Substrate," Journal of Electronic Materials, vol. 38, no. 1, pp. 54-60, 2008.
 A. Haque, B. H. Lim, A. S. M. A. Haseeb, and H. H. Masjuki, "Die attach properties of Zn–Al–Mg–Ga based high-temperature lead-free solder on Cu lead-frame," Journal of Materials Science: Materials in Electronics, journal article vol. 23, no. 1, pp. 115-123, January 01 2012.
 R. Cao, J. H. Sun, J. H. Chen, and P.-C. Wang, "Cold Metal Transfer Joining of Aluminum AA6061-T6-to-Galvanized Boron Steel," Journal of Manufacturing Science and Engineering, vol. 136, no. 5, p. 051015, 2014.
 S. Kim, K.-S. Kim, S.-S. Kim, and K. Suganuma, "Interfacial reaction and die attach properties of Zn-Sn high-temperature solders," Journal of Electronic Materials, vol. 38, no. 2, pp. 266-272, 2009.
 R. Mahmudi and M. Eslami, "Impression creep behavior of Zn-Sn high-temperature lead-free solders," Journal of electronic materials, vol. 39, no. 11, pp. 2495-2502, 2010.
 R. Mahmudi and M. Eslami, "Shear strength of the Zn–Sn high-temperature lead-free solders," Journal of Materials Science: Materials in Electronics, vol. 22, no. 8, pp. 1168-1172, 2011.
 N.-C. Lee, Reflow Soldering Processes. Elsevier, pp.57-89, 2002.
 N.-C. Lee, Reflow Soldering Processes. Elsevier, pp.239-250, 2002.
 J.-X. Wang, S.-B. Xue, Z.-J. Han, S.-L. Yu, Y. Chen, Y.-P. Shi, and H. Wang, "Effects of rare earth Ce on microstructures, solderability of Sn–Ag–Cu and Sn–Cu–Ni solders as well as mechanical properties of soldered joints," Journal of Alloys and Compounds, vol. 467, no. 1-2, pp. 219-226, 2009.
 C. L. Wu, D. Yu, C. Law, and L. Wang, "The properties of Sn-9Zn lead-free solder alloys doped with trace rare earth elements," Journal of Electronic Materials, vol. 31, no. 9, pp. 921-927, 2002.
 C. Wu, C. Law, D. Yu, and L. Wang, "The wettability and microstructure of Sn-Zn-RE alloys," Journal of Electronic Materials, vol. 32, no. 2, pp. 63-69, 2003.
 Y.-H. Hu, S.-B. Xue, H. Wang, H. Ye, Z.-X. Xiao, and L.-l. Gao, "Effects of rare earth element Nd on the solderability and microstructure of Sn–Zn lead-free solder," Journal of Materials Science: Materials in Electronics, vol. 22, no. 5, pp. 481-487, 2010.
 X. Chen, A. Hu, M. Li, and D. Mao, "Study on the properties of Sn–9Zn–xCr lead-free solder," Journal of Alloys and Compounds, vol. 460, no. 1-2, pp. 478-484, 2008.
 I. E. Anderson, J. W. Walleser, J. L. Harringa, F. Laabs, and A. Kracher, "Nucleation Control and Thermal Aging Resistance of Near-Eutectic Sn-Ag-Cu-X Solder Joints by Alloy Design," Journal of Electronic Materials, vol. 38, no. 12, pp. 2770-2779, 2009.
 I. Anderson, J. Foley, B. Cook, J. Harringa, R. Terpstra, and O. Unal, "Alloying effects in near-eutectic Sn-Ag-Cu solder alloys for improved microstructural stability," Journal of Electronic Materials, vol. 30, no. 9, pp. 1050-1059, 2001.
 Y. Wang, Y. Lin, C. Tu, and C. Kao, "Effects of minor Fe, Co, and Ni additions on the reaction between SnAgCu solder and Cu," Journal of Alloys and Compounds, vol. 478, no. 1-2, pp. 121-127, 2009.
 Y. W. Wang, Y. W. Lin, C. T. Tu, and C. R. Kao, "Effects of minor Fe, Co, and Ni additions on the reaction between SnAgCu solder and Cu," Journal of Alloys and Compounds, vol. 478, no. 1-2, pp. 121-127, 2009.
 J.-C. Liu, G. Zhang, J.-S. Ma, and K. Suganuma, "Ti addition to enhance corrosion resistance of Sn–Zn solder alloy by tailoring microstructure," Journal of Alloys and Compounds, vol. 644, pp. 113-118, 2015.
 C. L. Chuang, L. C. Tsao, H. K. Lin, and L. P. Feng, "Effects of small amount of active Ti element additions on microstructure and property of Sn3.5Ag0.5Cu solder," Materials Science and Engineering: A, vol. 558, pp. 478-484, 2012.
 W. M. Chen, S. K. Kang, and C. R. Kao, "Effects of Ti addition to Sn–Ag and Sn–Cu solders," Journal of Alloys and Compounds, vol. 520, pp. 244-249, 2012.
 P.-C. Liu, "The interfacial reaction between Sn-Zn series solders and Ag substrate."
 K. Suganuma, T. Murata, H. Noguchi, and Y. Toyoda, "Heat resistance of Sn–9Zn solder/Cu interface with or without coating," Journal of Materials Research, vol. 15, no. 4, pp. 884-891, 2000.
 R. Hultgren, P. D. Desai, D. T. Hawkins, M. Gleiser, and K. K. Kelley, "Selected values of the thermodynamic properties of binary alloys," National Standard Reference Data System1973.
 J.-E. Lee, K.-S. Kim, K. Suganuma, J. Takenaka, and K. Hagio, "Interfacial properties of Zn–Sn alloys as high temperature lead-free solder on Cu substrate," Materials Transactions, vol. 46, no. 11, pp. 2413-2418, 2005.
 J.-M. Song, M.-J. Lin, K.-H. Hsieh, T.-Y. Pai, Y.-S. Lai, and Y.-T. Chiu, "Ball impact reliability of Zn-Sn high-temperature solder joints bonded with different substrates," Journal of electronic materials, vol. 42, no. 9, pp. 2813-2821, 2013.
 C.-M. Chen and C.-H. Chen, "Interfacial reactions between eutectic SnZn solder and bulk or thin-film Cu substrates," Journal of Electronic Materials, vol. 36, no. 10, pp. 1363-1371, 2007.
 黃偉誌, "鋅錫鈦高溫無鉛銲錫氧化及界面潤濕反應行為之研究," 材料科學及工程學系, 成功大學, 2016年.